Method for determining validity of system information block and apparatus supporting same

ABSTRACT

A method for determining the validity of a system information block (SIB) by a terminal in a wireless communication system, and an apparatus supporting the same. The method includes: receiving, from a serving cell, a first version index indicating a version of a first system information block; determining a valid sub index to be mapped to a terminal capability of the terminal, among a plurality of sub-indices configuring the first version index; and comparing a valid sub index of a second version index indicating a version of a second system information block stored in the terminal with a valid sub index of the first version index, so as to determine whether the version of the first system information block is identical to the version of the second system information block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/494,684, filed on Sep. 16, 2019, which is a National Stageapplication under 35 U.S.C. § 371 of International Application No.PCT/KR2018/003028, filed on Mar. 15, 2018, which claims the benefit ofU.S. Provisional Application No. 62/471,967 filed on Mar. 16, 2017. Thedisclosures of the prior applications are incorporated herein byreference in their entirety.

BACKGROUND Technical Field

The present invention relates to a technology for identifying a versionof a system information block based on characteristics of a terminal.

Related Art

In order to meet the demand for wireless data traffic since the 4thgeneration (4G) communication system came to the market, there areongoing efforts to develop enhanced 5th generation (5G) communicationsystems or pre-5G communication systems. For the reasons, the 5Gcommunication system or pre-5G communication system is called the beyond4G network communication system or post long-term evolution (LTE)system.

As the amount of data communication increases, on-demand systeminformation (OSI) has been proposed. In the case of the on-demand systeminformation, the UE can request system information from the cell, andthe network receiving the request can transmit the requested systeminformation to the UE. On this wise, discussions on utilizing radioresource efficiently are constantly fulfilled.

In addition, the system information may be divided into a minimum SI andother SI. The minimum SI may be broadcast periodically. The minimum SImay be provided through basic information required for initial access tothe cell and information for periodically acquiring other SI broadcastsor on demand.

SUMMARY

Even if unnecessary information is changed in the terminal among theinformation included in the system information block, when the terminalrequests and receives the transmission of the new version of systeminformation block due to the change, the radio resource and power may beunnecessarily consumed.

According to an embodiment of the present invention, in a method fordetermining the validity of a system information block (SIB) by aterminal in a wireless communication system, provided is the methodcomprises the steps of: receiving, from a serving cell, a first versionindex indicating a version of a first system information block;determining a valid sub index to be mapped to a terminal capability ofthe terminal, among a plurality of sub-indices configuring the firstversion index; and comparing a valid sub index of a second version indexindicating a version of a second system information block stored in theterminal with a valid sub index of the first version index, so as todetermine whether the version of the first system information block isidentical to the version of the second system information block.

The method may further comprise the step of determining that the secondsystem information block is valid in the serving cell and applying thesecond system information block to the serving cell, when it isdetermined that the version of the first system information block isidentical to the version of the second system information block.

The method may further comprise the step of requesting transmission ofthe first system information block to the serving cell, when it isdetermined that the version of the first system information block isdifferent from the version of the second system information block.

A sub-index except for a valid sub-index of the first version indexamong the sub-indexes configuring the first version index may bedifferent from a sub-index except for a valid sub-index of the secondversion index among the sub-indexes configuring the second versionindex.

The terminal capability may be determined by at least one of a servicesupported by the terminal, a version of the terminal, and a category ofthe terminal.

The first version index and the second version index may be eachconfigured for a plurality of bits, and the valid sub index may beconfigured to indicate one or more numbers listed at a specific positionin the plurality of bits according to the terminal capability.

The method may further comprises the step of receiving configurationinformation regarding a position in the column of the valid sub indexcorresponding to the terminal capability from the serving cell, beforeperforming the step of determining the valid sub index.

The configuration information may be periodically received from theserving cell.

The configuration information may be provided for each systeminformation block.

The first system information block may indicate a current version of thesystem information block that is valid in the changed serving cell,after a cell reselection procedure of the terminal is performed.

The first system information block may indicate a changed systeminformation block, when the terminal receives a system informationchange notification from the serving cell.

According to another embodiment of the present invention, in a terminalfor determining the validity of a system information block (SIB) in awireless communication system, provided are the terminal comprising: amemory; a transceiver; and a processor coupled to the memory and thetransceiver, and wherein the processor configured to: receive, from aserving cell, a first version index indicating a version of a firstsystem information block, determine a valid sub index to be mapped to aterminal capability of the terminal, among a plurality of sub-indicesconfiguring the first version index, and compare a valid sub index of asecond version index indicating a version of a second system informationblock stored in the terminal with a valid sub index of the first versionindex, so as to determine whether the version of the first systeminformation block is identical to the version of the second systeminformation block.

The processor may be configured to determine that the second systeminformation block is valid in the serving cell and apply the secondsystem information block to the serving cell, when it is determined thatthe version of the first system information block is identical to theversion of the second system information block.

The processor may be configured to request transmission of the firstsystem information block to the serving cell, when it is determined thatthe version of the first system information block is different from theversion of the second system information block.

A sub-index except for a valid sub-index of the first version indexamong the sub-indexes configuring the first version index may bedifferent from a sub-index except for a valid sub-index of the secondversion index among the sub-indexes configuring the second versionindex.

By comparing the valid sub-indexes among the version indices of thesystem information block, it is possible to identify the version of thesystem information block without considering whether unnecessaryinformation in the system information block is changed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows LTE system architecture.

FIG. 2 shows a control plane of a radio interface protocol of an LTEsystem.

FIG. 3 shows a user plane of a radio interface protocol of an LTEsystem.

FIG. 4 shows a structure of 5G system.

FIG. 5 shows an example of transmitting a master information block(MIB), a system information block1 (SIB1), and other SIBs.

FIG. 6 shows an update of system information.

FIG. 7 shows transmission of system information.

FIG. 8 shows a structure of a version index of a system informationblock according to an embodiment of the present invention.

FIG. 9 is a flowchart illustrating a method of determining the validityof a system information block according to an embodiment of the presentinvention.

FIG. 10 is a flowchart illustrating a method of determining the validityof a system information block according to an embodiment of the presentinvention.

FIG. 11 is a block diagram illustrating a wireless apparatus in which anembodiment of the present invention can be implemented.

DETAILED DESCRIPTION

The technology described below can be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), etc. The CDMA canbe implemented with a radio technology such as universal terrestrialradio access (UTRA) or CDMA-2000. The TDMA can be implemented with aradio technology such as global system for mobile communications(GSM)/general packet ratio service (GPRS)/enhanced data rate for GSMevolution (EDGE). The OFDMA can be implemented with a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA (E-UTRA), etc.IEEE 802.16m is evolved from IEEE 802.16e, and provides backwardcompatibility with a system based on the IEEE 802.16e. The UTRA is apart of a universal mobile telecommunication system (UMTS). 3rdgeneration partnership project (3GPP) long term evolution (LTE) is apart of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTE uses theOFDMA in a downlink and uses the SC-FDMA in an uplink. LTE-advanced(LTE-A) is an evolution of the LTE. 5G is an evolution of the LTE-A.

For clarity, the following description will focus on LTE-A/5G. However,technical features of the present invention are not limited thereto.

FIG. 1 shows LTE system architecture. The communication network iswidely deployed to provide a variety of communication services such asvoice over internet protocol (VoIP) through IMS and packet data.

Referring to FIG. 1, the LTE system architecture includes one or moreuser equipment (UE; 10), an evolved-UMTS terrestrial radio accessnetwork (E-UTRAN) and an evolved packet core (EPC). The UE 10 refers tocommunication equipment carried by a user. The UE 10 may be fixed ormobile, and may be referred to as another terminology, such as a mobilestation (MS), a user terminal (UT), a subscriber station (SS), awireless device, etc.

The E-UTRAN includes one or more evolved node-B (eNB) 20, and aplurality of UEs may be located in one cell. The eNB 20 provides an endpoint of a control plane and a user plane to the UE 10. The eNB 20 isgenerally a fixed station that communicates with the UE 10 and may bereferred to as another terminology, such as a base station (BS), a basetransceiver system (BTS), an access point, etc. One eNB 20 may bedeployed per cell. There are one or more cells within the coverage ofthe eNB 20. A single cell is configured to have one of bandwidthsselected from 1.25, 2.5, 5, 10, and 20 MHz, etc., and provides downlinkor uplink transmission services to several UEs. In this case, differentcells can be configured to provide different bandwidths.

Hereinafter, a downlink (DL) denotes communication from the eNB 20 tothe UE 10, and an uplink (UL) denotes communication from the UE 10 tothe eNB 20. In the DL, a transmitter may be a part of the eNB 20, and areceiver may be a part of the UE 10. In the UL, the transmitter may be apart of the UE 10, and the receiver may be a part of the eNB 20.

The EPC includes a mobility management entity (MME) which is in chargeof control plane functions, and a serving gateway (S-GW) which is incharge of user plane functions. The MME/S-GW 30 may be positioned at theend of the network and connected to an external network. The MME has UEaccess information or UE capability information, and such informationmay be primarily used in UE mobility management. The S-GW is a gatewayof which an endpoint is an E-UTRAN. The MME/S-GW 30 provides an endpoint of a session and mobility management function for the UE 10. TheEPC may further include a packet data network (PDN) gateway (PDN-GW).The PDN-GW is a gateway of which an endpoint is a PDN.

The MME provides various functions including non-access stratum (NAS)signaling to eNBs 20, NAS signaling security, access stratum (AS)security control, Inter core network (CN) node signaling for mobilitybetween 3GPP access networks, idle mode UE reachability (includingcontrol and execution of paging retransmission), tracking area listmanagement (for UE in idle and active mode), P-GW and S-GW selection,MME selection for handovers with MME change, serving GPRS support node(SGSN) selection for handovers to 2G or 3G 3GPP access networks,roaming, authentication, bearer management functions including dedicatedbearer establishment, support for public warning system (PWS) (whichincludes earthquake and tsunami warning system (ETWS) and commercialmobile alert system (CMAS)) message transmission. The S-GW host providesassorted functions including per-user based packet filtering (by e.g.,deep packet inspection), lawful interception, UE Internet protocol (IP)address allocation, transport level packet marking in the DL, UL and DLservice level charging, gating and rate enforcement, DL rate enforcementbased on APN-AMBR. For clarity MME/S-GW 30 will be referred to hereinsimply as a “gateway,” but it is understood that this entity includesboth the MME and S-GW.

Interfaces for transmitting user traffic or control traffic may be used.The UE 10 and the eNB 20 are connected by means of a Uu interface. TheeNBs 20 are interconnected by means of an X2 interface. Neighboring eNBsmay have a meshed network structure that has the X2 interface. The eNBs20 are connected to the EPC by means of an S1 interface. The eNBs 20 areconnected to the MME by means of an S1-MME interface, and are connectedto the S-GW by means of S1-U interface. The Si interface supports amany-to—

many relation between the eNB 20 and the MME/S-GW. The eNB 20 mayperform functions of selection for gateway 30, routing toward thegateway 30 during a radio resource control (RRC) activation, schedulingand transmitting of paging messages, scheduling and transmitting ofbroadcast channel (BCH) information, dynamic allocation of resources tothe UEs 10 in both UL and DL, configuration and provisioning of eNBmeasurements, radio bearer control, radio admission control (RAC), andconnection mobility control in LTE ACTIVE state. In the EPC, and asnoted above, gateway 30 may perform functions of paging origination,LTE_IDLE state management, ciphering of the user plane, SAE bearercontrol, and ciphering and integrity protection of NAS signaling.

FIG. 2 shows a control plane of a radio interface protocol of an LTEsystem. FIG. 3 shows a user plane of a radio interface protocol of anLTE system.

Layers of a radio interface protocol between the UE and the E-UTRAN maybe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. The radio interface protocol between the UE and the E-UTRAN maybe horizontally divided into a physical layer, a data link layer, and anetwork layer, and may be vertically divided into a control plane(C-plane) which is a protocol stack for control signal transmission anda user plane (U-plane) which is a protocol stack for data informationtransmission. The layers of the radio interface protocol exist in pairsat the UE and the E-UTRAN, and are in charge of data transmission of theUu interface.

A physical (PHY) layer belongs to the L1. The PHY layer provides ahigher layer with an information transfer service through a physicalchannel. The PHY layer is connected to a medium access control (MAC)layer, which is a higher layer of the PHY layer, through a transportchannel. A physical channel is mapped to the transport channel. Data istransferred between the MAC layer and the PHY layer through thetransport channel. Between different PHY layers, i.e., a PHY layer of atransmitter and a PHY layer of a receiver, data is transferred throughthe physical channel using radio resources. The physical channel ismodulated using an orthogonal frequency division multiplexing (OFDM)scheme, and utilizes time and frequency as a radio resource.

The PHY layer uses several physical control channels. A physicaldownlink control channel (PDCCH) reports to a UE about resourceallocation of a paging channel (PCH) and a downlink shared channel(DL-SCH), and hybrid automatic repeat request (HARQ) information relatedto the DL-SCH. The PDCCH may carry a UL grant for reporting to the UEabout resource allocation of UL transmission. A physical control formatindicator channel (PCFICH) reports the number of OFDM symbols used forPDCCHs to the UE, and is transmitted in every subframe. A physicalhybrid ARQ indicator channel (PHICH) carries an HARQ acknowledgement(ACK)/non-acknowledgement (NACK) signal in response to UL transmission.A physical uplink control channel (PUCCH) carries UL control informationsuch as HARQ ACK/NACK for DL transmission, scheduling request, and CQI.A physical uplink shared channel (PUSCH) carries a UL-uplink sharedchannel (SCH).

A physical channel consists of a plurality of subframes in time domainand a plurality of subcarriers in frequency domain. One subframeconsists of a plurality of symbols in the time domain. One subframeconsists of a plurality of resource blocks (RBs). One RB consists of aplurality of symbols and a plurality of subcarriers. In addition, eachsubframe may use specific subcarriers of specific symbols of acorresponding subframe for a PDCCH. For example, a first symbol of thesubframe may be used for the PDCCH. The PDCCH carries dynamic allocatedresources, such as a physical resource block (PRB) and modulation andcoding scheme (MCS). A transmission time interval (TTI) which is a unittime for data transmission may be equal to a length of one subframe. Thelength of one subframe may be 1 ms.

The transport channel is classified into a common transport channel anda dedicated transport channel according to whether the channel is sharedor not. A DL transport channel for transmitting data from the network tothe UE includes a broadcast channel (BCH) for transmitting systeminformation, a paging channel (PCH) for transmitting a paging message, aDL-SCH for transmitting user traffic or control signals, etc. The DL-SCHsupports HARQ, dynamic link adaptation by varying the modulation, codingand transmit power, and both dynamic and semi-static resourceallocation. The DL-SCH also may enable broadcast in the entire cell andthe use of beamforming. The system information carries one or moresystem information blocks. All system information blocks may betransmitted with the same periodicity. Traffic or control signals of amultimedia broadcast/multicast service (MBMS) may be transmitted throughthe DL-SCH or a multicast channel (MCH).

A UL transport channel for transmitting data from the UE to the networkincludes a random access channel (RACH) for transmitting an initialcontrol message, a UL-SCH for transmitting user traffic or controlsignals, etc. The UL-SCH supports HARQ and dynamic link adaptation byvarying the transmit power and potentially modulation and coding. TheUL-SCH also may enable the use of beamforming. The RACH is normally usedfor initial access to a cell.

A MAC layer belongs to the L2. The MAC layer provides services to aradio link control (RLC) layer, which is a higher layer of the MAClayer, via a logical channel. The MAC layer provides a function ofmapping multiple logical channels to multiple transport channels. TheMAC layer also provides a function of logical channel multiplexing bymapping multiple logical channels to a single transport channel. A MACsublayer provides data transfer services on logical channels.

The logical channels are classified into control channels fortransferring control plane information and traffic channels fortransferring user plane information, according to a type of transmittedinformation. That is, a set of logical channel types is defined fordifferent data transfer services offered by the MAC layer. The logicalchannels are located above the transport channel, and are mapped to thetransport channels.

The control channels are used for transfer of control plane informationonly. The control channels provided by the MAC layer include a broadcastcontrol channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH) and adedicated control channel (DCCH). The BCCH is a downlink channel forbroadcasting system control information. The PCCH is a downlink channelthat transfers paging information and is used when the network does notknow the location cell of a UE. The CCCH is used by UEs having no RRCconnection with the network. The MCCH is a point-to-multipoint downlinkchannel used for transmitting MBMS control information from the networkto a UE. The DCCH is a point-to-point bi-directional channel used by UEshaving an RRC connection that transmits dedicated control informationbetween a UE and the network.

Traffic channels are used for the transfer of user plane informationonly. The traffic channels provided by the MAC layer include a dedicatedtraffic channel (DTCH) and a multicast traffic channel (MTCH). The DTCHis a point-to-point channel, dedicated to one UE for the transfer ofuser information and can exist in both uplink and downlink. The MTCH isa point-to-multipoint downlink channel for transmitting traffic datafrom the network to the UE.

Uplink connections between logical channels and transport channelsinclude the DCCH that can be mapped to the UL-SCH, the DTCH that can bemapped to the UL-SCH and the CCCH that can be mapped to the UL-SCH.Downlink connections between logical channels and transport channelsinclude the BCCH that can be mapped to the BCH or DL-SCH, the PCCH thatcan be mapped to the PCH, the DCCH that can be mapped to the DL-SCH, andthe DTCH that can be mapped to the DL-SCH, the MCCH that can be mappedto the MCH, and the MTCH that can be mapped to the MCH.

An RLC layer belongs to the L2. The RLC layer provides a function ofadjusting a size of data, so as to be suitable for a lower layer totransmit the data, by concatenating and segmenting the data receivedfrom a higher layer in a radio section. In addition, to ensure a varietyof quality of service (QoS) required by a radio bearer (RB), the RLClayer provides three operation modes, i.e., a transparent mode (TM), anunacknowledged mode (UM), and an acknowledged mode (AM). The AM RLCprovides a retransmission function through an automatic repeat request(ARQ) for reliable data transmission. Meanwhile, a function of the RLClayer may be implemented with a functional block inside the MAC layer.In this case, the RLC layer may not exist.

A packet data convergence protocol (PDCP) layer belongs to the L2. ThePDCP layer provides a function of header compression function thatreduces unnecessary control information such that data being transmittedby employing IP packets, such as IPv4 or IPv6, can be efficientlytransmitted over a radio interface that has a relatively smallbandwidth. The header compression increases transmission efficiency inthe radio section by transmitting only necessary information in a headerof the data. In addition, the PDCP layer provides a function ofsecurity. The function of security includes ciphering which preventsinspection of third parties, and integrity protection which preventsdata manipulation of third parties.

A radio resource control (RRC) layer belongs to the L3. The RLC layer islocated at the lowest portion of the L3, and is only defined in thecontrol plane. The RRC layer takes a role of controlling a radioresource between the UE and the network. For this, the UE and thenetwork exchange an RRC message through the RRC layer. The RRC layercontrols logical channels, transport channels, and physical channels inrelation to the configuration, reconfiguration, and release of RBs. AnRB is a logical path provided by the L1 and L2 for data delivery betweenthe UE and the network. That is, the RB signifies a service provided theL2 for data transmission between the UE and E-UTRAN. The configurationof the RB implies a process for specifying a radio protocol layer andchannel properties to provide a particular service and for determiningrespective detailed parameters and operations. The RB is classified intotwo types, i.e., a signaling RB (SRB) and a data RB (DRB). The SRB isused as a path for transmitting an RRC message in the control plane. TheDRB is used as a path for transmitting user data in the user plane.

A non-access stratum (NAS) layer belongs to an upper layer of the RRClayer and serves to perform session management, mobility management, orthe like.

Referring to FIG. 2, the RLC and MAC layers (terminated in the eNB onthe network side) may perform functions such as scheduling, automaticrepeat request (ARQ), and hybrid automatic repeat request (HARD). TheRRC layer (terminated in the eNB on the network side) may performfunctions such as broadcasting, paging, RRC connection management, RBcontrol, mobility functions, and UE measurement reporting andcontrolling. The NAS control protocol (terminated in the MME of gatewayon the network side) may perform functions such as a SAE bearermanagement, authentication, LTE_IDLE mobility handling, pagingorigination in LTE_IDLE, and security control for the signaling betweenthe gateway and UE.

Referring to FIG. 3, the RLC and MAC layers (terminated in the eNB onthe network side) may perform the same functions for the control plane.The PDCP layer (terminated in the eNB on the network side) may performthe user plane functions such as header compression, integrityprotection, and ciphering.

Hereinafter, a 5G Network Structure is Described.

FIG. 4 shows a structure of a 5G system.

In case of an evolved packet core (EPC) having a core network structureof the existing evolved packet system (EPS), a function, a referencepoint, a protocol, or the like is defined for each entity such as amobility management entity (MME), a serving gateway (S-GW), a packetdata network gateway (P-GW), or the like.

On the other hand, in case of a 5G core network (or a NextGen corenetwork), a function, a reference point, a protocol, or the like isdefined for each network function (NF). That is, in the 5G core network,the function, the reference point, the protocol, or the like is notdefined for each entity.

Referring to FIG. 4, the 5G system structure includes at least one UE10, a next generation-radio access network (NG-RAN), and a nextgeneration core (NGC).

The NG-RAN may include at least one gNB 40, and a plurality of UEs maybe present in one cell. The gNB 40 provides the UE with end points ofthe control plane and the user plane. The gNB 40 is generally a fixedstation that communicates with the UE 10 and may be referred to asanother terminology, such as a base station (BS), a base transceiversystem (BTS), an access point, or the like. One gNB 40 may be arrangedin every cell. At least one cell may be present in a coverage of the gNB40.

The NGC may include an access and mobility function (AMF) and a sessionmanagement function (SMF) which are responsible for a function of acontrol plane. The AMF may be responsible for a mobility managementfunction, and the SMF may be responsible for a session managementfunction. The NGC may include a user plane function (UPF) which isresponsible for a function of a user plane.

Interfaces for transmitting user traffic or control traffic may be used.The UE 10 and the gNB 40 may be connected by means of a Uu interface.The gNBs 40 may be interconnected by means of an X2 interface.Neighboring gNBs 40 may have a meshed network structure based on an Xninterface. The gNBs 40 may be connected to an NGC by means of an NGinterface. The gNBs 40 may be connected to an AMF by means of an NG-Cinterface, and may be connected to a UPF by means of an NG-U interface.The NG interface supports a many-to-many-relation between the gNB 40 andthe AMF/UPF 50.

A gNB host may perform functions such as functions for radio resourcemanagement, IP header compression and encryption of user data stream,selection of an AMF at UE attachment when no routing to an AMF can bedetermined from the information provided by the UE, routing of userplane data towards UPF(s), scheduling and transmission of pagingmessages (originated from the AMF), scheduling and transmission ofsystem broadcast information (originated from the AMF or O&M), ormeasurement and measurement reporting configuration for mobility andscheduling.

An access and mobility function (AMF) host may perform primary functionssuch as NAS signalling termination, NAS signalling security, AS securitycontrol, inter CN node signalling for mobility between 3GPP accessnetworks, idle mode UE reachability (including control and execution ofpaging retransmission), tracking area list management (for UE in idleand active mode), AMF selection for handovers with AMF change, accessauthentication, or access authorization including check of roamingrights.

A user plane function (UPF) host may perform primary functions such asanchor point for Intra-/inter-RAT mobility (when applicable), externalPDU session point of interconnect to data network, packet routing &forwarding, packet inspection and user plane part of policy ruleenforcement, traffic usage reporting, uplink classifier to supportrouting traffic flows to a data network, branching point to supportmulti-homed PDU session, QoS handling for user plane, e.g. packetfiltering, gating, UL/DL rate enforcement, uplink traffic verification(SDF to QoS flow mapping), transport level packet marking in the uplinkand downlink, or downlink packet buffering and downlink datanotification triggering.

A session management function (SMF) host may perform primary functionssuch as session management, UE IP address allocation and management,selection and control of UP function, configuring traffic steering atUPF to route traffic to proper destination, controlling part of policyenforcement and QoS, or downlink data notification.

Hereinafter, System Information Will be Described.

FIG. 5 shows an example of transmitting a master information block(MIB), a system information blockl (SIB1), and other SIBs.

An LTE cell broadcasts basic parameters necessary for an operation of anIDLE_MODE UE and a CONNECTED_MODE UE via a plurality of separateinformation blocks. Examples of the information blocks include an MIB,SIB1, SIB2, and other system information blocks (or SIBn).

The MIB includes the most essential parameters needed for a UE to accessa cell. Referring to FIG. 5, an MIB message is broadcast through a BCHaccording to a periodicity of 40 ms, and MIB transmission is repeated inall radio frames within the periodicity of 40 ms. The UE receives an SIBmessage using the parameters received via the MIB.

There are different types of SIBs.

SIB1 includes pieces of information associated with cell access, andparticularly includes scheduling information on other SIBs (SIB2 toSIBn) than the SIB1. SIBs having the same transmission periodicity amongthe SIBs other than the SIB1 are transferred via the same systeminformation (SI) message. Thus, scheduling information includes amapping relationship between each SIB and the SI message. The SI messageis transmitted within an SI-window in a time domain, and each SI messageis associated with one SI-window. Since SI-windows for different piecesof SI do not overlap, only one SI message is transmitted within anySI-window. Thus, scheduling information includes a length of theSI-window and an SI transmission periodicity. Time/frequency fortransmitting the SI message is determined by dynamic scheduling of a BS.The SIB1 is broadcast through a downlink shared channel (DL SCH)according to a periodicity of eight radio frames (that is, 80-msperiodicity), and the SIB1 is repeatedly retransmitted on a fifthsubframe of an SFN-mod-2 radio frame within the 80-ms periodicity.

SIB2 includes necessary information for a UE to access a cell. The SIB2includes information on an uplink cell bandwidth, a random accessparameter, a parameter related to uplink power control, or the like.

SIB3 includes cell reselection information. SIB4 includes frequencyinformation on a serving cell and intra-frequency information on aneighboring cell related to cell reselection. SIBS includes frequencyinformation on a different E-UTRA frequency and inter-frequencyinformation on a neighboring cell related to cell reselection. SIB6includes frequency information on a UTRA frequency and information on aUTRA neighboring cell related to cell reselection. SIB7 includesfrequency information on a GERAN frequency related to cell reselection.SIB8 includes information on a neighboring cell.

SIB9 includes a Home eNodeB (HeNB) identity (ID). SIB10 to SIB12 includea public warning message, for example, for earthquake warning. SIB14 isused to support enhanced access barring and controls UEs to access acell. SIB15 includes information needed to receive an MBMS at contiguouscarrier frequencies. SIB16 includes information related to GPS time andcoordinated universal time (UTC). SIB17 includes RAN auxiliaryinformation.

Not all SIBs are always required to be present. For example, the SIB9 isnot needed in a mode in which a provider establishes an HeNB, and theSIB13 is not needed if a cell provides no MBMS.

System information is commonly applied to all UEs accessing a cell, andUEs need to always maintain up-to-date system information to perform anappropriate operation. When the system information is changed, the UEsneed to know in advance the time at which the BS transmits new systeminformation. In order that the BS and the UE mutually recognize a radioframe period for transmitting the new system information, the concept ofBCCH modification period is introduced which is described below indetail.

FIG. 6 shows an update of system information.

Referring to FIG. 6, a BS, which intends to update system information inan (n+1)th modification period, notifies in advance UEs of an update ofsystem information in an nth modification period. A UE, which isnotified of the update of the system information in the nth modificationperiod, receives and applies new system information at the verybeginning of the (n+1)th modification period. When the update of thesystem information is scheduled, the BS includes a system informationmodification indicator in a paging message. Generally, a paging messageis a message received by an idle-mode UE. However, since the update ofthe system information is notified through the paging message, aconnected-mode UE also needs to receive the paging message at times andto identify the update of the system information.

System information in NG-RAN (or new radio access technology) isdescribed. As the amount of data communication increases, there is acontinuous discussion for efficient use of radio resources. As part ofthis effort, on-demand system information (OSI) has been proposed. Inthe case of on-demand system information, the terminal may requestsystem information from the cell, and the network receiving the requestmay transmit the requested system information to the terminal

FIG. 7 shows transmission of system information. System information canbe divided into minimum SI and other SI. The minimum SI may be calledanother term, for example, a remaining SI. In step S70, the base station(e.g., gNB) may provide a minimum SI to the UE. The minimum SI may bebroadcast periodically, and may be provided without further request. Theminimum SI may be provided through basic information required forinitial access to the cell and information for periodically acquiringother SI broadcasts or on demand. The minimum SI includes at least SFN,a list of PLMNs, cell IDs, cell camping parameters, and RACH parameters.If the network allows an on-demand mechanism, the parameters required torequest other SI blocks (e.g., RACH preamble requests, if required) areincluded in the minimum SI. In step S72, the base station may send otherSI to the UE. Other SIs may be broadcast periodically and optionallyprovided. Other SI includes everything that is not broadcast in theminimum SI. In the cell reselection procedure, neighbor cell informationis considered as other SI. In S74, the other SI may be broadcast orprovided in a dedicated manner by the network or upon request from theUE. The UE may request one or more SIs or all SIs (e.g., SIBs) in asingle request. For other SIs required by the UE, before the UEtransmits other SI requests, the UE needs to know whether the UE isavailable in the cell and whether it is broadcast. This may be done byexamining a minimum SI that provides scheduling information for theother SI, including SIB type, validity information, SI periodicity, andSI-window information based on LTE. The scheduling information in theminimum SI includes an indicator indicating whether the correspondingSI-block is broadcast periodically or provided when needed. If theminimum SI indicates that the SIB is not broadcast, the UE does notassume that the SIB is broadcast periodically in the SI-window every SIperiod. Thus, the UE can send an SI request to receive this SIB. Afterthe UE sends an SI request to receive the requested SIB, it monitors theSI window of the requested SIB in one or more SI cycles of that SIB

Meanwhile, any one system information block may include a large amountof information. A particular terminal may only need some of the largeamounts of information in the system information block. For example, ifSIB2 including SSAC (specific service access barring) relatedinformation is provided in an LTE network, a terminal supporting Release9 of 3GPP may require SSAC related information in SIB2. It is notnecessary for supporting terminals. If only SSAC-related information ofSIB2 is changed, the terminal supporting release 8 does not need toconsider this change. However, even when unnecessary information ischanged to a specific terminal among information included in SIB2, whenthe specific terminal receives a new SIB2 due to such a change, radioresources and power may be unnecessarily consumed.

Hereinafter, a method of identifying system information according to anembodiment of the present invention will be described.

A terminal according to an embodiment of the present invention mayidentify a version of the system information block by using only a validsub-index corresponding to the terminal among the version indexes of thesystem information block. The version index of the system informationblock is an identifier indicating the version of the system informationblock. When a version of the system information block is changed as someof the information in the system information block is changed, a versionindex different from the existing system information block may beallocated to the changed system information block. Specifically, theterminal may identify information valid for the terminal according tothe terminal capability in the system information block, and may checkthe version of the system information block based on the sub-indexindicating the identified information. Here, the terminal capability maybe determined according to a service and the like that the terminal cansupport. Specifically, the terminal capability may be determinedaccording to the version of the release, the version of the terminal,the category of the terminal, the type of the terminal, and the like.

The version index of the system information block may be configured of aplurality of sub indexes. In addition, various pieces of informationincluded in the system information block may be mapped to a plurality ofsub indexes, respectively. The sub index may be given in acharacteristic unit of information included in the system informationblock. In other words, different sub-indexes may be given to differentinformation included in the system information block. The terminal maydetermine a valid sub-index corresponding to the terminal capability ofthe terminal among the sub-indexes, and may identify a version of thecorresponding system information block only with the valid sub-index.

FIG. 8 shows a structure of a version index of a system informationblock according to an embodiment of the present invention.

Referring to FIG. 8, the version index of the system information block Amay be configured of a plurality of sub indexes. For example, theversion index of the system block A may be 8 bits, and may be composedof three sub indexes (first sub index to third sub index). In addition,the first sub index and the second sub index may be 3 bits, and thethird sub index may be 2 bits. However, the version index, the number ofbits of each sub-index, and the number of sub-indexes according to anembodiment of the present invention are not particularly limited.

As illustrated in FIG. 8, the system information block may includeinformation corresponding to the first sub index, informationcorresponding to the second sub index, and information corresponding tothe third sub index. For example, the information corresponding to thefirst sub index may be information related to the release 8, theinformation corresponding to the second sub index may be informationrelated to the release 9, and the information corresponding to the thirdsub index may be information related to the released 10. The terminalsupporting only the release 8 may identify a version of the systeminformation block using only the first sub-index. In the above example,the information corresponding to the second sub-index and the thirdsub-index is unnecessary information for the terminal supporting onlythe release 8. Therefore, even if the information corresponding to thesecond sub-index and the third sub-index of the system information blockis changed, if the information corresponding to the first sub-index isidentical to each other, the terminal supporting only the release 8 maydetermine that the versions of the system information block is identicalto each other.

When the terminal capability of the terminal is mapped to only the firstsub index, the terminal may decode only a portion of the systeminformation block mapped to the first sub index. That is, the terminalcannot decode a portion mapped to the second sub index and the third subindex in the portion of the system information block. The terminal maydetermine that the first sub index is a valid sub index, and the secondsub index and the third sub index are invalid sub indexes. The terminalmay identify the version of the system information block using only thefirst sub-index (first to third bits). Referring to FIG. 8, the terminalmay determine that a system information block having a version index of00010101 and a system information block having a version index of00001010 are the same version. This is because the value of the firstsub index (first to third bits) valid for the terminal is the same as“000”.

If the terminal capability of the terminal is mapped to the first subindex and the second sub index of the system information block, theterminal may use the first sub index (first to third bits) and thesecond sub index (fourth to sixth bits) to identify the version of thesystem information block. Referring to FIG. 8, the terminal maydetermine that a system information block having a version index of00010101 and a system information block having a version index of00001010 are different versions. This is because the values of the firstsub index (the first to third bits) and the second sub index (the fourthto sixth bits) valid for the terminal are different from each other by“000101” and “000010”, respectively. In addition, it may be determinedthat the system information block having the version index 00010101 andthe system information block having the version index 00010110 are thesame version. This is because the values of the first sub index (firstto third bits) and the second sub index (fourth to sixth bits) valid forthe terminal are the same as “000101”.

If the terminal capability of the terminal is mapped to the first subindex, the second sub index, and the third sub index of the systeminformation block, the terminal may identify the version of the systeminformation block using all the sub indexes. In other words, when allsub indexes, that is, all version indexes is identical to each other,the terminal may consider the system information block as the sameversion.

The version index configuration information of the system informationblock may include information about a valid sub-index of the systeminformation block for a specific terminal. The version indexconfiguration information may be configured differently for eachterminal and for each system information block. The version indexconfiguration information of the system information block may includethe following information.

-   -   Option 1: It is possible to map the characteristic or capability        of the terminal to the valid bit. The terminal capability of the        terminal may be determined according to the 3GPP release        version, version of the terminal, category of the terminal, and        the like. For example, the first bit may be mapped to        information related to the release 8 and the second bit may be        mapped to information related to the release 9. As another        example, the second to fourth bits may be mapped to information        related to the terminal category 1.    -   Option 2: It is possible to map the terminal capability of the        terminal to the sub index. In this case, the sub index may be        mapped to valid bits valid for the terminal among the bits        configuring the version index. For example, a terminal        supporting the release 1 may be mapped to the first sub index,        and the first sub index may be mapped to the first to third bits        of the bits configuring the version index.

The configuration information of the version index of the systeminformation block may be broadcast periodically. That is, theconfiguration information of the version index may be treated as minimumsystem information periodically transmitted to the terminal without aseparate request. In addition, configuration information of the versionindex of the system information block may be provided for each systeminformation block.

FIG. 9 is a flowchart illustrating a method of determining the validityof a system information block according to an embodiment of the presentinvention. In the present embodiment, the first terminal and the secondterminal may be terminals supporting the release 1 and the release 2,respectively. The release 1 and the release 2 are not limited to 3GPPreleases here. In addition, the first terminal and the second terminalmay be staying in the initial first cell.

In step S902, the first terminal and the second terminal may receiveminimum system information from a serving cell, that is, the first cell.The minimum system information may include version index configurationinformation of a system information block. According to an embodiment,the version index configuration information may indicate that an indexof the system information block is configured for 8 bits, the 7th bit isassociated with the release 2, and the 8th bit is associated with therelease 4. In general, a terminal supporting the release 4 requiresinformation associated with the release 2. On the other hand, theterminal supporting the release 2 does not require informationassociated with the release 4. Therefore, the version indexconfiguration information may mean the following items.

-   -   The terminal supporting the release 1 may consider the first to        sixth bits in the version index of the system information block        as a valid sub-index.    -   The terminal supporting the release 2 or 3 may consider the        first to seventh bits in the version index of the system        information block as a valid sub-index.    -   The terminal supporting the release 4 may consider the first to        eighth bits in the version index of the system information block        as a valid sub-index.

In step S904, the first terminal and the second terminal may receive thefirst system information block SIB1 and the second system informationblock SIB2 together with the version index from the serving cell. Inthis case, the first system information block and the second systeminformation block may be provided to the terminal at the request of theterminal as other system information (other SI). The first systeminformation block and the second system information block may be, forexample, SIB9 and SIB13, respectively. According to an embodiment, theversion index of the first system information block transmitted to thefirst terminal may be “10110000”. In this case, the first terminal mayconsider the version index of the first system information block as“101100XX” according to the version index configuration informationreceived in S902. In other words, the first terminal may consider thefirst to sixth bits of the version index of the system information blockas a valid sub-index for the first terminal, and may identify theversion of the system information block by considering only the first tosixth regardless of the seventh to eighth bits. In addition, the versionindex of the second system information block transmitted to the firstterminal may be “11100011”. Similarly, the first terminal may considerthe version index of the second system information block as “111000XX”.

Meanwhile, the version index of the first system information blocktransmitted to the second terminal may be “10110000”, and the secondterminal may consider that a version index of the first systeminformation block as “1011000X” according to the version indexconfiguration information received in S902. In other words, the secondterminal may consider the first to seventh bits of the version index ofthe system information block as a valid sub-index for the secondterminal, and may identify the version of the system information blockby considering only the first to seventh bits regardless of the eighthbit. In addition, the version index of the second system informationblock transmitted to the second terminal may be “11100011”. Similarly,the second terminal may consider the version index of the second systeminformation block as “1110001X”.

In step S906, the first terminal and the second terminal may perform acell reselection procedure. Accordingly, the first terminal and thesecond terminal may stay in the second cell.

In step S908, the first terminal and the second terminal may receiveminimum system information from the changed serving cell, that is, thesecond cell. The minimum system information may include a version indexof each system information block. The version index of the first systeminformation block included in the minimum system information may be“10110001” and the version index of the second system information blockmay be “11100000”. In this step, the first terminal and the secondterminal may receive only the version index of each system informationblock, and may not receive each of the system information itself.

According to an embodiment, the first terminal may consider that theversion index of the first system information block of the changedserving cell is “101100XX”. This is because, according to the versionindex configuration information of the minimum system informationreceived in step S902, the first terminal may consider that the first tosixth bits of the version index of the system information block arevalid sub-indexes for the first terminal. Similarly, the first terminalmay consider that the version index of the second system informationblock of the changed serving cell is “111000XX”.

Meanwhile, the second terminal may consider that the version index ofthe second system information block of the changed serving cell is“1011000X”. This is because, according to the version indexconfiguration information of the minimum system information received instep S902, the second terminal may consider the first to seventh bits ofthe version index of the system information block as the valid sub-indexfor the first terminal. Similarly, the second terminal may consider thatthe version index of the second system information block of the changedserving cell is “1110000X”.

The first terminal may determine that the first system information blockand the second system information block received from the first cell andthe first system information block and the second system informationblock received from the second cell are the same version.

In an embodiment, the version index of the first system informationblock received from the first cell is “10110000” and the version indexof the first system information block received from the second cell is“10110001”. In this case, the first terminal may compare the first tosixth bits of the version index of the first system information blockreceived from the first cell and the first to sixth bits of the versionindex of the first system information block received from the secondcell. Since the version index of each first system information blockreceived from the first cell and the second cell are both “101100XX”,the first terminal may determine that the versions of each first systeminformation block is identical to each other.

In addition, the version index of the second system information blockreceived from the first cell is “11100011” and the version index of thesecond system information block received from the second cell is“11100000”. In this case, the first terminal may compare the first tosixth bits of the version index of the second system information blockreceived from the first cell and the first to sixth bits of the versionindex of the second system information block received from the secondcell. Since the version index of each second system information blockreceived from the first cell and the second cell are both “111000XX”,the first terminal may determine that the versions of each second systeminformation blocks is identical to each other

Accordingly, the first terminal may know that the first systeminformation block and the second system information block received fromthe first cell are also valid in the second cell. Accordingly, the firstterminal may maintain the first system information block and the secondsystem information block received from the first cell and apply thefirst system information block and the second system information blockto the second cell.

Meanwhile, the second terminal may determine that the first systeminformation block received from the first cell and the first systeminformation block received from the second cell are the same version.The version index of the first system information block received fromthe first cell is “10110000” and the version index of the first systeminformation block received from the second cell is “10110001”. In thiscase, the second terminal may compare the first to seventh bits of theversion index of the first system information block received from thefirst cell and the first to seventh bits of the version index of thefirst system information block received from the second cell. Since theversion index of each first system information block received from thefirst cell and the second cell is both “1011000X”, the second terminalmay determine that the versions of each first system information blockis identical to each other.

However, the second terminal may determine that the second systeminformation block received from the first cell and the second systeminformation block received from the second cell are different versions.The version index of the second system information block received fromthe first cell is “11100011” and the version index of the second systeminformation block received from the second cell is “11100000”. In thiscase, the second terminal may compare the first to seventh bits of theversion index of the second system information block received from thefirst cell and the first to seventh bits of the version index of thesecond system information block received from the second cell. Since theversion index of the second system information block received from thefirst cell is “1110001X” and the version index of each second systeminformation block received from the second cell is “1110000X”, thesecond terminal may determine that the version of the second systeminformation block received from the first cell and the second systeminformation block received from the second cell is different from eachother.

If the second terminal has a second system information block having aversion index of “1110000X”, the second system information block may beused. However, if the second terminal does not have the second systeminformation block having the version index “1110000X”, the transmissionof the second system information block having the version index“1110000X” to the second cell may be requested.

In step S910, the second terminal may request transmission of a secondsystem information block having a version index of “1110000X” (e.g., asystem information block having a version index of 11100000) to thesecond cell. In step S912, the second terminal may request the secondsystem information block having a version index of “1110000X” to thesecond cell, and then the second terminal may apply the second systeminformation block having a received version index of “1110000X” to thesecond cell.

In step S914, the first terminal and the second terminal may receive asystem information change notification from the second cell. The systeminformation change notification may indicate that the first systeminformation block is changed from a version having a version index of“10110001” to a version having a version index of “10110010”. Inaddition, the system information change notification may indicate thatthe second system information block is changed from a version having aversion index of “11100000” to a version having a version index of“11100010”.

The first terminal may determine that the first system information blockand the second system information block are not changed. Specifically,the first terminal may compare the first to sixth bits of the versionindex of the first system information block and the second systeminformation block to identify the version of the system informationblock. Accordingly, the first terminal may consider both the versionindex 10110001 of the first system information block before the changeand the version index 10110010 of the first system information blockafter the change as “101100XX”. In addition, the first terminal mayconsider both the version index 11100000 of the second systeminformation block before the change and the version index 11100010 ofthe second system information block after the change as “111000XX”.

In contrast, the second terminal may determine that the first systeminformation block and the second system information block have beenchanged. Specifically, the second terminal may compare the first toseventh bits of the version index of the first system information blockand the second system information block to identify the version of thesystem information block. According to an embodiment, since the versionindex 10110001 of the first system information block before the changeand the version index 10110010 of the first system information blockafter the change are different from each other as “1011000X” and“1011001X”, according to an embodiment of the present invention, thefirst system information block may be determined to have changed.Therefore, the second terminal should receive the changed first systeminformation block from the second cell. Also, the second terminal maydetermine that the version index 11100000 of the second systeminformation block before the change and the version index 11100010 ofthe second system information block after the change are different fromeach other as “1110000X” and “1110001X”. However, in step S904, thesecond terminal has already received the system information block havinga version index of “11100011” from the first cell. Since the second cellconsiders the version index “11100010” and the version index “11100011”to be the same, the system information block having a version index“11100011” which is already stored may be applied to the second cell.

In step S916, the second terminal may request transmission of the firstsystem information block to the second cell. Specifically, the secondterminal may request the first cell of the first system informationblock having a version index of “1011001X” to the second cell. In stepS918, the second terminal may receive the first system information blockhaving a version index of “1011001X” from the base station and apply itto the second cell.

FIG. 10 is a flowchart illustrating a method of determining the validityof a system information block according to an embodiment of the presentinvention.

In step S1002, the terminal may receive a first version index indicatinga version of the first system information block from the serving cell.In step S1004, the terminal may determine a valid sub-index mapped tothe terminal capability of the terminal among the plurality ofsub-indexes configuring the first version index. In step S1006, theterminal may compare the valid sub-index of the second version indexindicating the version of the second system information block stored inthe terminal with the valid sub-index of the first version index, todetermine whether the version of the first system information block andthe versions of the second system information block is identical to eachother.

If it is determined that the version of the first system informationblock and the version of the second system information block isidentical to each other, the terminal may determine that the secondsystem information block is valid in the serving cell to apply thesecond system information block to the serving cell. If it is determinedthat the version of the first system information block is different fromthe version of the second system information block, the terminal mayrequest transmission of the first system information block to theserving cell. The sub-index except for a valid sub-index of the firstversion index among the sub-indexes configuring the first version indexmay be different from the sub-index except for a valid sub-index of thesecond version index among the sub-indexes configuring the secondversion index. The terminal capability may be determined by at least oneof a service supported by the terminal, a version of the terminal, and acategory of the terminal. Each of the first version index and the secondversion index may be configured for a plurality of bits, and the validsub-index may be configured to indicate one or more numbers listed at aspecific position in the plurality of bits according to the terminalcapability. The terminal may receive, from the serving cell,configuration information regarding a position in the column of thevalid sub index corresponding to the terminal capability before the stepof performing the determining of the valid sub index. The configurationinformation may be periodically received from the serving cell. Theconfiguration information may be provided for each system informationblock. The first system information block may indicate a current versionof the system information block valid in the changed serving cell, afterperforming the cell reselection procedure of the terminal. The firstsystem information block may indicate a changed system information blockwhen the terminal receives a system information change notification fromthe serving cell.

FIG. 11 is a block diagram illustrating a wireless apparatus in which anembodiment of the present invention can be implemented.

A BS 1100 includes a processor 1101, a memory 1102, and a radiofrequency (RF) unit 1103. The memory 1102 is coupled to the processor1101, and stores a variety of information for driving the processor1101. The RF unit 1103 is coupled to the processor 1101, and transmitsand/or receives a radio signal. The processor 1101 implements theproposed functions, procedures, and/or methods. In the aforementionedembodiments, an operation of the BS may be implemented by the processor1101.

A UE 1110 includes a processor 1111, a memory 1112, and an RF unit 1113.The memory 1112 is coupled to the processor 1111, and stores a varietyof information for driving the processor 1111. The RF unit 1113 iscoupled to the processor 1111, and transmits and/or receives a radiosignal. The processor 61 implements the proposed functions, procedures,and/or methods. In the aforementioned embodiments, an operation of theUE 1110 may be implemented by the processor 1111.

The processors 1111 may include application-specific integrated circuit(ASIC), other chipset, logic circuit and/or data processing device. Thememories may include read-only memory (ROM), random access memory (RAM),flash memory, memory card, storage medium and/or other storage device.The RF units may include baseband circuitry to process radio frequencysignals. When the embodiments are implemented in software, thetechniques described herein can be implemented with modules (e.g.,procedures, functions, and so on) that perform the functions describedherein. The modules can be stored in memories and executed byprocessors. The memories can be implemented within the processors orexternal to the processors in which case those can be communicativelycoupled to the processors via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope and spirit of the present disclosure.

What has been described above includes examples of the various aspects.It is, of course, not possible to describe every conceivable combinationof components or methodologies for purposes of describing the variousaspects, but one of ordinary skill in the art may recognize that manyfurther combinations and permutations are possible. Accordingly, thesubject specification is intended to embrace all such alternations,modifications and variations that fall within the scope of the appendedclaims.

What is claimed is:
 1. A method for determining the validity of a systeminformation block (SIB) by a terminal in a wireless communicationsystem, the method comprises the steps of: receiving, from a servingcell, first information related to a version of a first systeminformation block, wherein a second system information block is storedin the terminal, and second information is related to a version of thesecond system information; determining a first value of the firstinformation and a second value of the second information, wherein thefirst information is received with the first system information block,and the second information is stored in the terminal with the secondsystem information block; and comparing the second value of the secondinformation with the first value of the first information, so as todetermine whether the second system information block stored in theterminal is valid.
 2. The method of claim 1, further comprisingdetermining that the second system information block is valid in theserving cell and applying the second system information block to theserving cell, when it is determined that the version of the first systeminformation block is identical to the version of the second systeminformation block.
 3. The method of claim 2, the version of the firstsystem information block is identical to the version of the secondsystem information block, when it is determined that the first value ofthe first information is identical to the second value of the secondinformation.
 4. The method of claim 1, further comprising requestingtransmission of the first system information block to the serving cell,when it is determined that the version of the first system informationblock is different from the version of the second system informationblock.
 5. The method of claim 1, the first value of the firstinformation is composed of a plurality of bits among bits of the firstinformation, and the second value of the second information is composedof a plurality of bits among bits of the second information.
 6. Themethod of claim 1, wherein the first value and the second value are eachmapped to a terminal capability of the terminal, and the terminalcapability is determined by at least one of a service supported by theterminal, a version of the terminal, and a category of the terminal. 7.The method of claim 1, wherein the first information and the secondinformation are each configured for a plurality of bits, and the firstvalue and the second value are each configured to indicate one or morenumbers listed at a specific position in the plurality of bits accordingto the terminal capability.
 8. The method of claim 6, further comprisingreceiving configuration information regarding a position in the columnof the first value and the second value corresponding to the terminalcapability from the serving cell, before performing the step ofdetermining the first value and the second value.
 9. The method of claim8, wherein the configuration information is periodically received fromthe serving cell.
 10. The method of claim 8, wherein the configurationinformation is provided for each system information block.
 11. Themethod of claim 1, wherein the first system information block indicatesa current version of the system information block that is valid in thechanged serving cell, after a cell reselection procedure of the terminalis performed.
 12. The method of claim 1, wherein the first systeminformation block indicates a changed system information block, when theterminal receives a system information change notification from theserving cell.
 13. A terminal for determining the validity of a systeminformation block (SIB) in a wireless communication system, comprising:a memory; a transceiver; and a processor coupled to the memory and thetransceiver, and wherein the processor configured to: receive, from aserving cell, first information related to a version of a first systeminformation block, wherein a second system information block is storedin the terminal, and second information is related to a version of thesecond system information; determine a first value of the firstinformation and a second value of the second information, wherein thefirst information is received with the first system information block,and the second information is stored in the terminal with the secondsystem information block; and compare the second value of the secondinformation with the first value of the first information, so as todetermine whether the second system information block stored in theterminal is valid.
 14. The terminal of claim 13, wherein the processorfurther configured to determine that the second system information blockis valid in the serving cell and apply the second system informationblock to the serving cell, when it is determined that the version of thefirst system information block is identical to the version of the secondsystem information block.
 15. The terminal of claim 14, wherein theprocessor further configured to determine that the version of the firstsystem information block is identical to the version of the secondsystem information block, when it is determined that the first value ofthe first information is identical to the second value of the secondinformation.
 16. The terminal of claim 13, wherein the processor furtherconfigured to request transmission of the first system information blockto the serving cell, when it is determined that the version of the firstsystem information block is different from the version of the secondsystem information block.
 17. The terminal of claim 13, the first valueof the first information is composed of a plurality of bits among bitsof the first information, and the second value of the second informationis composed of a plurality of bits among bits of the second information.